CISM Radiation Belt Models CMIT Mary Hudson CISM

CISM Radiation Belt Models CMIT Mary Hudson CISM Seminar Nov 06

Van Allen Radiation Belts Slot region outer belt inner belt

Van Allen Belts-Plasmasphere Overlap Ring current

Solar Cycle Dependence of 2 -6 Me. V Electrons Li et al. , GRL, 2006

Van Allen Radiation Belts: Slot region variability Slot region outer belt inner belt SAMPEX electrons: 2 - 6 Me. V Outer belt slot region L=2 -3 inner belt

Effect on the Radiation Belts [Baker et al. , 2004, Nature] slot region new belt

March 91 Shock Acceleration 3. 5 Me. V at L=6. 6, t=0 (M =11, 150 Me. V/G) Elkington et al. , JASTP, 02; 04

MHD-Guiding Center Simulation Elkington et al. , JASTP, 2002; 2004

SAMPEX >10 Me. V Electron Injections

SAMPEX: Mar 91 decay+Feb 94 injection

Halloween 03 >10 Me. V Electron Injections

Global LFM-MHD Simulations of Magnetosphere n Solar wind measurements made WIND, ACE or IMP 8 (Feb 94, not Mar 91) n Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere

1994 Feb 21 Event: density

1994 Feb 21 Event: Ephi

Halloween ’ 03 Shock Injection initial E ~ 5 Me. V, R ~ 6 RE, final E ~15 Me. V, R ~ 2. 5 RE Kress et al. , 06

Halloween ’ 03 Shock Injection of >10 Me. V (W 0=1 -7 Me. V) Electrons

E_phi (left) and Solar Energetic Electron Trajectory (right) Halloween ‘ 03 solar energetic electron injection event Kress et al. , 2006

n Low altitude SAMPEX observations of > 10 Me. V electrons, injected 10/29/03 • E-1. 5 electron energy spectrum from several Me. V to > 15 Me. V • Initially not observed at SAMPEX due to eq injection Simulated pitch angle distribution->

Outer Belt Losses Due to Whistler Pitch Angle Scattering outer belt 2 -6 Me. V Slot Variability: [Lyons et al. , 1972] Hiss Whistler Mode

Losses due to Pitch Angle Scattering EMIC waves from ring current ions VLF waves from p’sheet electrons

MHD Fields Injection of Rad. Belt Electrons Elkington et al. , JASTP, 2004

MHD Fields Injection of Rad. Belt Electrons Elkington et al. , JASTP, 2004

Diffusion Rates vs. L Radial diffusion rates in model ULF wave fields ### # Selesnick & Blake 2000 LN D_LL ~ # Perry et al. , JGR, 05, includes δEφ, δBr, δB//, freq and L-dependent power Radial diffusion rates in model ULF wave fields D_LL ~ L^N Perry et al. , JGR, 2005, Include δEφ, δBr, δB//, freq and L-dependence 3 D trajectories N ~ 6 for no L-dep power, N ~ 12 with L dependence M=273 Me. V/G Tau(L, E) Summers 04 Elkington et al. , 2003 Braughtigam & Albert, 2000, N=6, 10; Perry et al. , 2006, N=6, 12

Solutions to diffusion equation using DLL from model ULF wave fields & and PSD from CRRES measurements in subsequent 10 -hr orbits to update inner and outer boundaries Perry et al. 2005 DLL=10 -2(L/4)^12 day-1 Dashed lines show CRRES measurements of PSD 61 days apart. Loss model based on Summers et al. 2004.

MHD-Driven Phase Space Density Radial Diffusion MHD-Test Particle AE 8 Max-Initialized, Sept 98 Storm Fei et al. , 2006

New belt example: 24 Nov 2001 Mazur et al. , AGU Monograph 165, 2006 Clear trapping of solar particles: 13 of 26 SEP penetration events inside L=4, 98 -03

Conclusions n n n n Drift time scale injection of multi- Me. V electrons: Strong compression of dayside magnetopause due to high speed CME Relativistic electron seed population at and beyond geosynchronous required Plasmasphere plays role intensifying E_phi Long-lived, energetic trapped population injected into slot region Well-described by CMIT without coupled RCM Intermediate storm timescale (hrs, days): changes in PSD described by radial diffusion & loss due to whistler (and EMIC) scattering Enhanced D_LL due to ULF waves needs further study with RCM coupled to CMIT, plasmasphere, ion outflow to populate m’sphere during IMF Bz<0

Drift Time Scale Injection from SSC’s Blake et al. , 2005

Mar 91 -Feb 91 Comparison